The present invention relates to a novel zinc magnesium titanate represented by the following formula (I):
Zn2xe2x88x92xMgx.yTiO4xe2x80x83xe2x80x83(I)
in which
x denotes a real number of 0.5 to 1.5; and
y denotes an integer of 1 or 2, and to a process for preparing the same and a thermoregulating functional composition which comprises zinc magnesium titanate of formula (I).
Particularly, the thermoregulating functional composition according to the present invention can reflect ultraviolet rays, visible rays and infrared rays irradiated from sun to inhibit the temperature increase and further, exhibits a good adiabatic property against low temperature to maintain uniformly the temperature of the coated product. Therefore, the composition of the present invention has a thermoregulating function for the product coated therewith and also imparts good light resistance and weather resistance properties to the coated product.
Japanese Laid-open Patent Publication No. (Hei) 8-3019 discloses acrylic acid copolymers or crosslinked gel, for example, N-isopropylacrylamide, N-isopropylmethacrylamide, N-pentylmethacrylamide, etc., which provides a good application feeling by changing the affinity to water depending on body temperature to alter the holding amount of water. U.S. Pat. No. 5,353,600 teaches a cosmetic case into which a thermoelectric refrigeration device with an electric cell is sandwiched. In addition, U.S. Pat. Nos. 5,237,838 and 4,892,226 disclose a portable cosmetic bag for protection of the content, which is sensitive to heat, from a possible heat degradation; and U.S. Pat. No. 3.732,702 teaches a cosmetic cabinet equipped with a cooling unit for dispersion of heat and moisture generated in using it in bathroom or locker room.
As the prior art relating to inorganic pigments for the purpose of thermal control, zinc titanate used for the surface of spacecraft has been known (see NASA Contract. Rep., NASA-CR-144310, 466 pp, 1976); U.S. Pat. No. 5,401,583 discloses the use of zinc oxide and titanium dioxide as a white coating; and U.S. Pat. Nos. 5,476,696 and 5,567,490 also describe zirconium silicate which is durable to darkening caused by X-ray and ultraviolet radiation.
However, these prior inorganic pigments have generally been used for protecting the product from the short-wavelength X-ray and ultraviolet rays irradiated from universal space, but any special study for the inorganic pigment to control thermal problems by effectively reflecting ultraviolet ray B (280xcx9c320nm), ultraviolet ray A (320xcx9c400nm), visible ray (400xcx9c760 nm) and infrared ray (over 760nm), rather than ultraviolet ray C (below 280 nm) which is screened by an ozone layer at the face of the earth, has not been made.
Further, as the prior patents relating to the process for preparing inorganic pigments Japanese Laid-open Patent Publication No. (Sho) 63-265819 and U.S. Pat. No. 3,607,338 teach the process which comprises sintering titanium dioxide and zinc oxide to prepare zinc titanate and then removing the remaining zinc oxide by dissolving it with an acid. However, the inorganic pigment as prepared by the process as mentioned above did not also effectively control ultraviolet ray B, ultraviolet ray A, visible rays and infrared rays.
Meanwhile, for example, U.S. Pat. No. 4,882,650 discloses the use of magnesium titanate prepared in the form of ceramics as a dielectric substance. However, this belongs to the different group of technology, which is never related to the present invention of which the purpose is to control the temperature.
Under such technical background, the present inventors have acknowledged the necessity of a novel composition which can uniformly maintain the temperature of the coatings regardless of outside environment, for example, under variable weather such as sultry summer or cold winter in which excessive sunlight is irradiated. In order to achieve such a purpose, we have studied the inorganic pigment having a novel thermoregulating function. As a result, we have identified that a ternary system-based composite oxide comprising zinc-magnesium-titanium reflects the most of light from some wavelength in the area of ultraviolet ray C to wavelength in the area of infrared rays to inhibit an increase in temperature, and displays an excellent adiabatic property against dramatic drop of temperature to exhibit a consistent temperature maintaining effect, and farther that the cosmetic or paint composition containing such composite oxide has a thermoregulating function, and thus completed the present invention.
Accordingly, the purpose of the present invention is to provide a novel zinc magnesium titanate represented by the following formula (I):
Zn2xe2x88x92xMgx.yTiO4xe2x80x83xe2x80x83(I)
in which
x denotes a real number of 0.5 to 1.5; and
y denotes an integer of 1 or 2.
Another purpose of the present invention is to provide a process for preparing the inorganic pigment of formula (I) as defined above.
Still another purpose of the present invention is to provide a composition having thermoregulating function which comprises the inorganic pigment of formula (I) as an effective component.